Peak-frequency mapping in detecting atrial ganglionated plexi in patients with functional bradycardia
T Kamakura, T Ikee, D Shako, S Oka, A Wakamiya, N Ueda, K Nakajima, K Nakasuka, M Wada, K Ishibashi, Y Inoue, K Miyamoto, T Aiba, K KusanoAbstract
Background
Standardised methods for the identification of ganglionated plexi (GP) are lacking. Peak-frequency (PF) mapping may serve as an effective approach for identifying atrial GP sites with fractionated potentials. Atrial GP detection has been indicated within a region characterised by high PF (≥600 Hz) in patients with functional bradycardia; however, the detailed anatomical associations between high PF regions and atrial GP-positive sites are yet to be established.
Purpose
In this study, we evaluated the use of PF mapping for the detection of atrial GP.
Methods
We evaluated the correlations between GP-positive sites and PF mapping in five consecutive patients who had undergone GP ablation for symptomatic functional bradycardia (two with cardioinhibitory reflex syncope, two with sick sinus syndrome, and one with atrioventricular block). Atrial GP were defined as areas with a positive vagal response during high-frequency stimulation or effective ablation sites (asystole during ablation for a left-sided GP, increased sinus rate for a right-sided GP, or shortening of the atrioventricular interval during ablation for a posteromedial left atrial GP [PMLGP]).
Results
We observed colocalisation of the GP and high PF regions (≥600 Hz) for the right superior GP (RSGP) in four patients (80%) and left superior GP (LSGP) in two patients (40%) (Figures 1 and 2), and no colocalisation of the GP and high PF regions in one patient (20%). The median PF of each GP site was significantly higher than those of the surrounding GP-negative sites: LSPG, 464.5 [interquartile range (IQR); 414.8–506] vs. 334 (IQR; 256.6–414.8), p < 0.0005; Marshall tract GPs, 384 (IQR; 344–506) vs. 286 (IQR; 195.8–367.8), p = 0.0025; RSGP, 506.5 (IQR; 433.5–582.8) vs. 359 (IQR; 266.8–501.8), p = 0.0051; PMLGPs, 448.5 (IQR; 411–501.8) vs. 312 (IQR; 236–358), p = 0.0002. However, in the right-sided GPs, high PF regions were observed in a wider area than in GP-positive sites, whereas PF mapping with the same threshold failed to detect the left-sided GPs (Figures 1 and 2).
Conclusion
Atrial GP sites showed a higher PF than the surrounding GP-negative sites, thereby indicating that PF mapping may facilitate atrial GP identification. However, PF mapping alone lacked specificity in identifying atrial GP-positive sites. Further studies are thus required to determine the optimal PF threshold for the detection of atrial GPs.Figure 1Figure 2